Fracture walker with horseshoe heel pad beneath insole

ABSTRACT

A method and apparatus for locating a calcaneus within a fracture walker is disclosed. The apparatus includes a locating device that has a notch formed therein, and an insole covering the locating device whereby the ankle forms a depression in the insole adjacent the notch when force is applied through the ankle on the insole.

FIELD OF THE INVENTION

The present invention generally relates to a fracture walker, and more particularly to a method and apparatus for locating the foot within a fracture walker.

BACKGROUND OF THE INVENTION

Fracture walkers are often used to stabilize the ankle and lower extremity to encourage healing after a surgery or injury. A typical fracture walker can be used to limit the ankle flexion to either a fixed position or to a chosen range of dorsiflexion and/or plantarflexion. A typical fracture walker includes a foot platform portion and a lower leg portion. Generally, adjustable hinges are located between these two portions in order to allow some degree of ankle movement or to lock the ankle from movement. A typical fracture walker is sized such that it can be used for either the right or left leg thereby requiring the foot portion to accommodate either a right or left foot. Accordingly, the foot portion is generally rectangular to accommodate the various shapes of feet. Generally, straps are provided to secure the lower extremity within a fracture walker. These straps are located across the forefoot and around the lower leg in order to tighten the foot portion and the lower leg portion. Typically, the rear of the foot portion is sized to accommodate a variety of ankles while providing for ankle movement and flexion.

When walking, the biomechanics of human gait involves the calcaneus, or heel bone, inverting and everting as the tibia rotates and counter rotates. This movement of the calcaneus occurs after heel strike and during the midstance and terminal stance phases of the walking cycle. Ideally, the non-parallel alignment of the midtarsal axes permits the foot to become rigid to support the body's weight and to provide a rigid lever for propulsion.

During heel strike with a fracture walker, the forefoot and lower limb above the ankle are secured within the fracture walker. A misalignment of step or nonlevel walking surface may result in a shifting or twisting of the foot platform as weight is applied through the lower limb (loading response phase of the walking cycle). This shifting or twisting can cause a loss of balance to the patient to the extent that additional weight is shifted to the lower limb as the upper body is rotated to regain balance. This twisting of the foot platform relative the upper body can cause an unrestrained calcaneus to relocate within the fracture walker. With the forefoot essentially immobile relative to the fracture walker, movement of the calcaneus relative to the fracture walker can occur to alter the ideal alignment of the midtarsal axes. During further movement (midstance), the calcaneus will not be properly positioned for supporting body weight. This misalignment can cause new injuries, prolong healing or complicate existing injuries.

A typical method for properly locating the calcaneus in a fracture walker involves wrapping pads around the vertical surfaces of the heel in order to position the calcaneus within the foot portion. These pads are wrapped around the heel and are required to fit tightly to prevent undesirable movement. Tightly restraining the ankle is undesirable for patients with an ankle injury and is a special concern for patients with edema in the lower extremity or diabetes. Additionally, the heel is ideally allowed to move within a fracture walker when the patient's weight is not being applied thereto. What is needed is an improved positioning system for a fracture walker to locate the calcaneus during weight bearing and heel strike.

SUMMARY OF THE INVENTION

In accordance with the teaching of the present invention, a method and apparatus for locating a calcaneus within a fracture walker is disclosed. In one form, the present invention provides a fracture walker having a foot platform with a base and an insole covering the base. A locating device is interposed between the foot platform and the insole. The locating device includes a fore portion having a notch therein extending to a forward surface. The locating device is adapted to locate a calcaneus within the fracture walker. In another form, the present invention provides a method of locating a calcaneus within a fracture walker wherein a locating device adapted to correctly locate the calcaneus laterally within a medial-lateral heel space adjacent the calcaneus within the fracture walker is provided.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 illustrates a perspective view of a fracture walker in accordance with the present invention;

FIG. 2 is a cutaway view of a left ankle located within the fracture walker of FIG. 1;

FIG. 3 is an exploded partial perspective view of the fracture walker of FIG. 1;

FIG. 4 is a perspective view of a locating device shown within a partial section of the fracture walker of FIG. 1;

FIG. 5 is an alternate embodiment of the locating device of FIG. 4; and

FIG. 6 is a further alternate embodiment of the locating device of FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment of a method and apparatus for locating a calcaneus within a fracture walker is merely exemplary in nature and is in no way intended to limit the invention, its applications or uses. It should be appreciated that the locating device, while shown as a horseshoe shaped member, may be any shape that allows the calcaneus to be properly positioned within a fracture walker.

FIG. 1 illustrates a fracture walker in accordance with the present invention referred to generally as numeral 10. Fracture walker 10 includes a foot platform 12, a pair of hinge assemblies 14, a leg assembly 16, a liner 18, straps 20, an insole 22, and a locating device 24. Foot platform 12 includes a base 26 with a rear lip 28 around the back of a foot and frame members 30 extending therefrom around the medial and lateral sides of a foot. Frame members 30 have strap attachment apertures 32 and hinge attachment locations 34 formed therein. Leg assembly 16 includes uprights 38 with hinge attachment apertures 40 and strap apertures 42 formed therein. Straps 20 include straps 20 a that are used to tighten leg assembly 16 and straps 20 b that are used to tighten base 26. Insole 22 is positioned on base 26 while covering foot platform 12. Locating device 24 is interposed between foot platform 12 and insole 22, as discussed below. Preferably, locating device 24 and insole 22 are constructed of foam. Even more preferably, the durometer hardness of locating device 24 is higher than the durometer hardness of insole 22.

FIGS. 2 and 3 illustrate insole 22 to include an outer edge 44, a rear portion 46, and a fore portion 48. As best seen in FIG. 4, locating device 24 includes a top surface 50, a bottom surface 52, an inside surface 54 defining a notch 56, a curved rear surface 58 defining a rearward portion 60, and a forward portion 62 having a forward surface 64.

Curved rear surface 58 and outer edge 44 at rear portion 46 of insole 22 are formed to contour lip 28 such that insole 22 and locating device 24 are restrained from lateral movement within fracture walker 10, as best seen in FIGS. 3 and 4. In this manner, insole 22 and locating device 24 can be positioned within foot platform 12 without the use of a guide or tool. Preferably, insole 22 and locating device 24 are affixed together and to foot platform 12 with an adhesive to prevent relative movement therebetween.

When assembled, straps 20 a are threaded through the strap apertures 42 of uprights 38, as best seen in FIG. 1. Each strap attachment aperture 32 has a chafe 72 attached thereto. Straps 20 b are threaded through chafes 72. Straps 20 a and straps 20 b are used to restrain the lower leg and the forefoot as discussed below. Hinge assemblies 14 attach uprights 38 and frame members 30 via hinge attachment apertures 40 and hinge attachment locations 34. Preferably, hinge assembly 14 can be either locked to restrain flexion by the ankle, or restrained in such a manner as to allow a certain degree of dorsiflexion and/or plantarflexion of the ankle when positioned within the fracture walker. Such hinge assemblies are well known in the art and, therefore, are not described in detail herein.

FIG. 2 illustrates a cutaway view of a partial lower extremity 78 within a fracture walker 10 wherein a left ankle 80 includes a calcaneus 82, a tibia 84, a fibula 86, ligaments 88, and flesh portion 90. Left ankle 80 is supported by fracture walker 10 on base 26. Preferably, liner 18 is form fitted about the lower extremity 78. Liner 18 is placed around left ankle 80 in order to provide a degree of cushioning and prevent chafing of the skin. Frame members 30 are shown to define a medial-lateral heel space 96 adjacent calcaneus 82 that is roughly twice the width at the base of left ankle 80. The heel space 96 allows the calcaneus 82 to invert and evert by anatomical rotation relative left ankle 80. Tibia 84 and fibia 86 are shown to fit within leg assembly 16 and frame members 30 of fracture walker 10 with relatively less medial-lateral ankle space when compared to the heel space 96. Left ankle 80 rests within liner 18 on insole 22 which is above locating device 24. Locating device 24 is positioned such that the notch 56 is located directly below calcaneus 82. As the weight of a patient is applied through ankle 80 and calcaneus 82 onto insole 22 and locating device 24, notch 56 allows insole 22 to flex downwardly such that a portion of the insole 22 is displaced into the notch 56, thereby forming a depression in a portion of insole 22. This displacement of insole 22 results in at least a portion of left ankle 80 with liner 18 attached thereon to reside in the depression. This depression is spaced from frame members 30 and inhibits medial-lateral movement of calcaneus 82 as medial-lateral forces are translated from calcaneus 82 through flesh portion 90, liner 18, and insole 22 to inner surface 54 of locating device 24. Thus, the ankle 80 is allowed heel space 96, but is correctly positioned by the locating device 24 during the calcaneus 82 weight bearing portion of walking.

When use of a fracture walker 10 is desired, the patient places the lower extremity 78 in liner 18. Preferably, liner 18 is a flexible, cushioned cloth member that is wrapped around the lower extremity 78 with overlapping portions. Liner 18 may include a plurality of hook and loop type stays to retain the position of liner 18 relative to lower extremity 78. Lower extremity 78 is then placed in fracture walker 10 and straps 20 are tightened to snug fracture walker 10 to the lower limb and forefoot.

As best seen in FIG. 2, fracture walker 10 will allow free medial-lateral rotation of the calcaneus 82 during non-weight bearing phases of walking. Thus provided, locating device 24 provides a system to locate calcaneus 82 during heel strike and weight bearing without unnecessarily restraining calcaneus 82. As will be appreciated, locating device 24 also provides a one-size-fits-all solution for locating the calcaneus 82, thereby eliminating the need for locating devices of various shapes. Additionally, locating device 24 can be cut from sheets of adhesive-backed foam for installation or retrofit into fracture walkers, thereby simplifying manufacture and installation.

FIG. 5 shows an alternate embodiment of locating device 24 illustrated as locating device 124 including a top surface 150, a bottom surface 152, an inside surface 154 defining a notch 156, a curved rear surface 158 defining a rearward portion 160, and a forward portion 162 having a forward surface 164. Inside surface 154 intersects top surface 150. FIG. 6 shows an additional alternate embodiment of locating device 24 illustrated as locating device 224 including a top surface 250, a bottom surface 252, an inside surface 254 defining a notch 256, and a curved rear surface 258 defining a rearward portion 260, and a forward portion 262 having a first forward surface 264 and a second forward surface 266. As will be appreciated, top surfaces 50, 150, or 250 and/or side surfaces 54, 64, 154, 164, 254, 262 or 266 can be beveled to provide a differing contour of insole 22 when weight is applied.

The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention. 

1. A fracture walker comprising: a foot platform having a base; an insole covering said base; and a locating device interposed between the foot platform and the insole, wherein the locating device has a fore portion, the fore portion having a notch therein extending to a forward surface, wherein the locating device is adapted to locate a calcaneus within the fracture walker.
 2. The fracture walker of claim 1, wherein the durometer hardness of the locating device is greater than the durometer hardness of the insole.
 3. The fracture walker of claim 1, further comprising a flexible liner, wherein the liner is interposed between a human lower extremity and the fracture walker.
 4. The fracture walker of claim 1, wherein the locating device is constructed of polyethylene foam.
 5. The fracture walker of claim 1, wherein the insole is constructed of polyethylene foam.
 6. The fracture walker of claim 1, further comprising a lip formed on said platform wherein the lip is adapted to abut the insole on said platform.
 7. The fracture walker of claim 1, wherein the locating device is adapted to accommodate the calcaneus of either a left foot or a right foot.
 8. A method of locating a calcaneus within a fracture walker comprising: providing a locating device for use with the fracture walker, the locating device being adapted to correctly locate the calcaneus laterally within a medial-lateral heel space adjacent the calcaneus within the fracture walker.
 9. The method of claim 8, wherein the calcaneus is correctly located by forming a depression.
 10. The method of claim 9, wherein forming the depression includes forming a notch within a locating device, wherein the locating device includes a generally flat body with a top surface, a bottom surface, and a fore portion, wherein at least the top surface and fore portion define the notch.
 11. The method of claim 10, wherein the notch extends to the bottom surface.
 12. The method of claim 10, further comprising: positioning the locating device within a fracture walker, wherein the bottom surface of the locating device is generally horizontal.
 13. The method of claim 10, further comprising: positioning an insole within the fracture walker, wherein the locating device is interposed between the insole and the fracture walker.
 14. The method of claim 13, wherein forming the depression includes: displacing a portion of the insole into the notch.
 15. The method of claim 10, further comprising: positioning an ankle within the fracture walker, wherein the ankle includes the calcaneus and the locating device is interposed between the ankle and the fracture walker, and the calcaneus is located generally above the notch.
 16. The method of claim 9, wherein forming the depression includes: applying a force through the calcaneus to the fracture walker such that the force forms the depression.
 17. The method of claim 9, wherein the depression is formed within an insole. 